DISC1 is associated with prefrontal cortical gray matter and positive symptoms in schizophrenia

Background: DISC1 is considered a susceptibility gene for schizophrenia and schizoaffective disorder, but little is known regarding the potential mechanisms through which it may confer increased risk. Given that DISC1 plays a role in cerebral cortex development, polymorphisms in this gene may have relevance for neurobiological models of schizophrenia that have implicated cortical deficits in its pathophysiology. Methods: We investigated whether the DISC1 leu607phe polymorphism was associated with prefrontal gray matter volumes using magnetic resonance imaging in a cohort of patients with schizophrenia (N = 19) and healthy volunteers (N = 25) and positive and negative symptoms in 200 patients with schizophrenia. Results: Among patients and healthy volunteers, phe carriers (N = 11) had significantly less gray matter in the superior frontal gyrus and anterior cingulate gyrus compared to leu/leu homozygotes (N = 33). Further, among patients left superior frontal gyrus gray matter volume was significantly negatively correlated with severity of hallucinations. In addition, patients who were phe carriers (N = 144) had significantly greater severity of positive symptoms (hallucinations) compared to patients who were leu/leu homozygotes (N = 56). Discussion: These findings implicate DISC1 in variation of prefrontal cortical volume and positive symptoms, thus providing a potential mechanism through which DISC1 may confer increased risk for schizophrenia or schizoaffective disorder.